Originally Posted by Captain Bill
What I feel has nothing to do with whether these units are transponders or not. If they transmit information when polled from another unit then they are in fact transponders, not transceivers. The op wanted to know if law enforcement could poll
his dsc to get his position without his knowledge. I simply stated that he may have been confusing dsc with ais. You have simply confirmed my statement with the proviso that if you have the transmtter turned off they cannot do so. Of course if you have it on you'll be announcing the same infrormation every couple of minutes anyway.
A transponder is a device that only responds to commands , ie its transmits a " response". aIs is primarily a transceiver in that its transits data without any command.
Anyone can issue message 18 requests to get the position data , but since such data is already being transmitted on a regular basis , I fail to see what point you are making. aIS does not transmit your information without your knowledge , I mean you switched it on to do just that thing , ie transmit you position !!!!
You make it sound like its " doing it behind your back " , that's tin hat stuff.